#include "BieuThuc.h"


BieuThuc* BieuThuc::tinhDaoHam(){
	if(bieuThuc == NULL){
		bieuThuc = this->timDaoHam();
	}
	return bieuThuc;
}

BieuThuc::BieuThuc(){
	bieuThuc = NULL;
}

//BieuThuc::~BieuThuc(){
//}










